Refrigeration device

ABSTRACT

An object is to provide a novel multi-stage refrigeration apparatus. The object is achieved by a refrigeration apparatus comprising a user-side heat transfer cycle that includes a user-side compressor, a user-side heat exchanger, a user-side pressure-reducing device, and a user-side cascade heat exchanger, and that circulates a user-side refrigerant; a heat-source-side heat transfer cycle that includes a heat-source-side compressor, a heat-source-side heat exchanger, a heat-source-side pressure-reducing device, and a heat-source-side cascade heat exchanger, and that circulates a heat-source-side refrigerant; a cascade heat exchanger configured to exchange heat between the user-side refrigerant of a user-side condenser and the heat-source-side refrigerant of a heat-source-side evaporator; and a control device, the user-side refrigerant having a boiling point of -30° C. or more and 25° C. or less, and the heat-source-side refrigerant having a boiling point of -55° C. or more and less than -30° C.

TECHNICAL FIELD

The present disclosure relates to a refrigeration apparatus.

BACKGROUND ART

Two-stage refrigeration apparatuses, which include a two-stage refrigerant cycle composed of a user-side heat transfer cycle and a heat-source-side heat transfer cycle, have been proposed (Patent Literature 1 and Patent Literature 2).

CITATION LIST Patent Literature

-   PTL 1: WO2015/140872 -   PTL 2: WO2015/140873

SUMMARY

A refrigeration apparatus comprising:

-   a user-side heat transfer cycle configured to circulate a user-side     refrigerant; -   a heat-source-side heat transfer cycle configured to circulate a     heat-source-side refrigerant; and -   a cascade heat exchanger configured to exchange heat between the     user-side refrigerant and the heat-source-side refrigerant, -   the user-side refrigerant having a boiling point of -30° C. or more     and 25° C. or less, and the heat-source-side refrigerant having a     boiling point of -55° C. or more and less than -30° C.

ADVANTAGEOUS EFFECTS OF INVENTION

The present disclosure provides a novel multi-stage refrigeration apparatus that allows the safe use of a refrigerant with a low boiling point, high pressure, high density, and high refrigerating capacity.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view for illustrating a configuration of the refrigeration apparatus of the present disclosure.

FIG. 2 is a view for illustrating a configuration of the refrigeration apparatus of the present disclosure.

DESCRIPTION OF EMBODIMENTS

The refrigeration apparatus of the present disclosure comprises:

-   a user-side heat transfer cycle configured to circulate a user-side     refrigerant; -   a heat-source-side heat transfer cycle configured to circulate a     heat-source-side refrigerant; and -   a cascade heat exchanger configured to exchange heat between the     user-side refrigerant and the heat-source-side refrigerant, -   the user-side refrigerant having a boiling point of -30° C. or more     and 25° C. or less, and the heat-source-side refrigerant having a     boiling point of -55° C. or more and less than -30° C.

The heat source side refers to the outdoor unit side and is also referred to as “the high-stage side,” “the high-temperature side,” or “the primary side.” From the viewpoint of improving performance, it is preferable to use a refrigerant with excellent refrigerant characteristics on the heat source side. The user side refers to the indoor unit side and is also referred to as “the low-stage side,” “the load side,” “the low-temperature side,” or “the secondary side.” From the viewpoint of cooling people and objects directly, it is preferable to use a highly safe refrigerant on the user side.

The refrigeration apparatus of the present disclosure is a multi-stage refrigeration apparatus that comprises at least a two-stage heat transfer cycle including a user-side heat transfer cycle (load-side heat medium circuit) and a heat-source-side heat medium circuit. The refrigeration apparatus of the present disclosure may comprise three or more heat transfer cycles.

As described later, in cooling operation, the cascade heat exchanger includes a heat-source-side cascade heat exchanger and a user-side cascade heat exchanger, and performs heat exchange. Specifically, in cooling operation, the refrigerant condenses in the user-side cascade heat exchanger, and the refrigerant evaporates in the heat-source-side cascade heat exchanger; thus, heat is transferred from the user side to the heat source side.

The user-side heat transfer cycle circulates the user-side refrigerant. The user-side heat transfer cycle may be a vapor compression refrigeration cycle. The user-side refrigeration cycle that is a vapor compression refrigeration cycle includes a user-side compressor, a user-side heat exchanger, a user-side pressure-reducing device, and a user-side cascade heat exchanger.

The user-side heat transfer cycle may also be a pump heat transfer cycle. The user-side heat transfer cycle that is a pump heat transfer cycle includes a pump, a user-side heat exchanger, and a user-side cascade heat exchanger.

For example, as shown in FIG. 1 , an expansion valve 13 or the like can be used as the user-side pressure-reducing device. Alternatively, another pressure-reducing device, such as a capillary tube, can be used as the user-side pressure-reducing device. In addition, the user-side heat exchanger can also be used as a cold source.

For example, when the amount of refrigerant required for the user-side heat transfer cycle significantly varies with changes in operating conditions, a liquid receiver 15 may be provided in a pipe communicating between a user-side cascade heat exchanger 12 and the user-side expansion valve 13, as shown in, for example, FIG. 2 .

It is preferred that the user-side heat transfer cycle includes a user-side high-pressure detection means for detecting the high pressure of the user-side heat transfer cycle and a user-side low-pressure detection means for detecting the low pressure of the user-side heat transfer cycle. It is also preferred that the user-side heat transfer cycle includes a user-side discharge temperature detection means for detecting the temperature of the user-side refrigerant discharged from the user-side compressor.

The user-side high-pressure detection means and the user-side low-pressure detection means are means for substantially detecting pressure. That is, the user-side high-pressure detection means and the user-side low-pressure detection means may detect the pressure of the user-side refrigerant itself or may detect other physical quantities that can be converted into the pressure of the user-side refrigerant.

The user-side discharge temperature detection means is a means for substantially detecting temperature. That is, the user-side discharge temperature detection means may detect the discharge temperature of the user-side refrigerant itself or may detect other physical quantities that can be converted into the discharge temperature of the user-side refrigerant.

For example, as shown in FIG. 1 , a user-side heat transfer cycle 10 includes a user-side high-pressure sensor 21 as a user-side high-pressure detection means, a user-side low-pressure sensor 22 as a user-side low-pressure detection means, and a user-side discharge temperature sensor 23 as a user-side discharge temperature detection means. The user-side high-pressure sensor 21 is preferably provided in a pipe communicating between the user-side cascade heat exchanger 12 and the user-side expansion valve 13. The user-side low-pressure sensor 22 is preferably provided in a pipe communicating between a user-side heat exchanger 14 and a user-side compressor 11. The user-side discharge temperature sensor 23 is preferably provided in a pipe communicating between the user-side compressor 11 and the user-side condenser 12. The user-side heat transfer cycle need not include some or all of these sensors if they are not needed.

The refrigeration apparatus of the present disclosure may further include a control device. A detection signal from the user-side high-pressure detection means, a detection signal from the user-side low-pressure detection means, and a detection signal from the user-side discharge temperature detection means are input to the control device. The control device controls the overall operation of the refrigeration apparatus of the present disclosure. The control device may be partially or entirely composed of, for example, a microcomputer, a microprocessor unit, or the like; updateable software such as firmware; or a program module or the like that is executed by a command from a CPU or the like.

The user-side refrigerant has a boiling point of -30° C. or more and 25° C. or less.

The heat-source-side heat transfer cycle circulates the heat-source-side refrigerant. The heat-source-side heat transfer cycle is preferably a vapor compression refrigeration cycle. The heat-source-side refrigeration cycle that is a vapor compression refrigeration cycle includes a heat-source-side compressor, a heat-source-side heat exchanger, a heat-source-side pressure-reducing device, and a heat-source-side cascade heat exchanger.

The heat-source-side compressor is of a variable capacity type. An expansion valve or the like can be used as the heat-source-side pressure-reducing device. Alternatively, another pressure-reducing device, such as a capillary tube, can be used as the heat-source-side pressure-reducing device.

The heat-source-side refrigerant has a boiling point of -55° C. or more and less than -30° C.

In cooling operation, a user-side condenser and a heat-source-side evaporator are incorporated in the cascade heat exchanger. When a non-azeotropic refrigerant mixture is used, heat exchange is performed between the user-side refrigerant in the user-side condenser and the heat-source-side refrigerant in the heat-source-side evaporator in the cascade heat exchanger. From the viewpoint of preventing a decrease in heat exchange efficiency due to the temperature glide, it is preferred that the flow directions of the heat-source-side refrigerant and the user-side refrigerant are in countercurrent flow in the cascade heat exchanger.

In heating operation, a user-side evaporator and a heat-source-side condenser are incorporated in the cascade heat exchanger. When a non-azeotropic refrigerant mixture is used, heat exchange is performed between the user-side refrigerant in the user-side evaporator and the heat-source-side refrigerant in the heat-source-side condenser in the cascade heat exchanger. From the viewpoint of preventing a decrease in heat exchange efficiency due to the temperature glide, it is preferred that the flow directions of the heat-source-side refrigerant and the user-side refrigerant are in countercurrent flow in the cascade heat exchanger.

According to the present disclosure, by using a refrigerant with a relatively high density and good performance that has a boiling point of -55° C. or more and less than -30° C. as the heat-source-side refrigerant, the efficiency of the refrigeration cycles can be maintained within a preferable range, and a refrigerant having a boiling point of -30° C. or more and 25° C. or less can be used as the user-side refrigerant. Thus, according to the present disclosure, use of a refrigerant with high performance on the heat source side ensures the performance of all cycles within a desirable range without using a refrigerant with a comparable level of performance on the user side. Some refrigerants have boiling points of -30° C. or more and 25° C. or less, but are excellent in terms of low GWP or low flammability. In the present disclosure, such refrigerants can also be suitably used.

According to the present disclosure, since such a refrigerant excellent in terms of low GWP can be used as the user-side refrigerant, it may be possible to reduce the total GWP of the refrigerants used while maintaining the performance of the entire apparatus. In this respect, the heat-source-side refrigerant preferably has a GWP of 750 or less, more preferably 500 or less, even more preferably 300 or less, and most preferably 150 or less; and the user-side refrigerant preferably has a GWP or 750 or less, more preferably 500 or less, even more preferably 300 or less, and most preferably 150 or less.

Alternatively, since a refrigerant excellent in terms of low flammability as described above can be used as the user-side refrigerant, the risk of harm to people from fire in the event of refrigerant leakage may be further reduced while maintaining the performance of the entire apparatus, by placing the user-side heat transfer cycle in an area in which harm to people is likely to occur. From the viewpoint that a safer refrigerant can be used on the user side, on which harm to people may be caused, the heat-source-side refrigerant preferably has a burning velocity of 10 cm/s or less, more preferably 9 cm/s or less, even more preferably 8 cm/s or less, and most preferably 7 cm/s or less; and the user-side refrigerant preferably has a burning velocity of 5 cm/s or less, more preferably 3 cm/s or less, even more preferably 2 cm/s or less, and most preferably 1.5 cm/s or less.

To make the refrigeration apparatus of the present disclosure suitable for practical use, it is preferable to use a refrigerant with a boiling point of 25° C. or less as the user-side refrigerant because its saturation vapor pressure can be made equal to or higher than atmospheric pressure. In this respect, the saturation pressure of the user-side refrigerant at 25° C. is preferably 0.0 MPaG or more, more preferably 0.01 MPaG or more, even more preferably 0.03 MPaG or more, and most preferably 0.05 MPaG or more; and the saturation pressure of the user-side refrigerant at 25° C. is preferably 5 MPaG or less, more preferably 4 MPaG or less, even more preferably 3 MPaG or less, and most preferably 2 MPaG or less.

To make the refrigeration apparatus of the present disclosure suitable for practical use, a refrigerant with a boiling point of -30° C. or more can be used as the user-side refrigerant to maintain its pressure at a level that does not exceed the withstanding pressure limit of the pipe. In this respect, as the user-side refrigerant, it is preferable to use a refrigerant with a boiling point of -30° C. or more, more preferable to use a refrigerant with a boiling point of -25° C. or more, and even more preferable to use a refrigerant with a boiling point of -20° C. or more.

From the viewpoint of reducing the impact on the global environment due to power consumption during use of the refrigeration cycles, the COP of the heat-source-side refrigerant is preferably 95% or more, more preferably 100% or more, even more preferably 101% or more, and still even more preferably 102% or more, compared with that of R410A.

From the viewpoint of reducing the impact of equipment manufacturing on the global environment by reducing the equipment size, the refrigerating capacity of the heat-source-side refrigerant is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, still even more preferably 90% or more, and most preferably 100% or more, compared with that of R410A.

To reduce the risk of harm to people from fire in the event of refrigerant leakage, examples of the combination of the heat-source-side refrigerant and the user-side refrigerant include a combination of a heat-source-side refrigerant having a burning velocity of 10 cm/s or less and a user-side refrigerant having a burning velocity of 3 cm/s or less. Examples of the combination of the heat-source-side refrigerant and the user-side refrigerant in the above case also include a combination of a heat-source-side refrigerant classified as Class 2L by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and a user-side refrigerant classified as Class A1 by ASHRAE.

When the heat-source-side refrigerant consists essentially of a single compound, examples of the heat-source-side refrigerant include HFO-1123, HFO-1132, R32, and the like. When the heat-source-side refrigerant is a mixture of a plurality of compounds, examples of the heat-source-side refrigerant include a mixture of at least two members selected from the group consisting of HFO-1123, HFO-1132, R1234yf, and R32; R452B; R454B; and the like. R452B is a mixture of R32, R125, and R1234yf (R32:R125:R1234yf (mass ratio) = 67:7:26), and R454B is a mixture of R32 and R1234yf (R32:R1234yf (mass ratio) = 68.9:31.1).

Specific examples of the heat-source-side refrigerant and the user-side refrigerant include the combinations shown in the table below.

TABLE 1 Heat-source-side refrigerant User-side refrigerant R410A R410A R410A R410A R410A R410A R513A R515B R1234ze(E) R1336mcy R1336mzz(E) R1224yd(Z) R32 R32 R32 R32 R32 R32 R513A R515B R1234ze(E) R1336mcy R1336mzz(E) R1224yd(Z) R454B R454B R454B R454B R454B R454B R513A R515B R1234ze(E) R1336mcy R1336mzz(E) R1224yd(Z) R452B R4528 R513A R515B R452B R452B R452B R452B R1234ze(E) R1336mcy R1336mzz(E) R1224yd(Z) R454C R454C R454C R454C R454C R454C R513A R515B R1234ze(E) R1336mcy R1336mzz(E) R1224yd(Z)

A mixture with HFO-1132 may contain at least one member selected from the group consisting of HFC32, HFO1234yf, HFO1234ze(E), and CO₂.

In the above, HFO-1132 is preferably HFO-1132(E), HFO-1132 (z), or HFO-1132a, and most preferably HFO-1132(E). A mixture with HFO-1123 may contain at least one member selected from the group consisting of HFC32, HFO1234yf, HFO1234ze(E), and CO₂.

Examples of the combination of the heat-source-side refrigerant and the user-side refrigerant include a combination of a heat-source-side refrigerant that is R32, R452B, or R454B, and a user-side refrigerant that is at least one member selected from the group consisting of R513A, R515A, R515B, R1224, R1234yf, R1234ze, R1233, and R1336. This combination is preferred in that the capacity of the refrigerant used on the heat source side is high.

Examples of the combination of the heat-source-side refrigerant and the user-side refrigerant include a combination of a heat-source-side refrigerant containing HFO-1132 and a user-side refrigerant that is at least one member selected from the group consisting of R513A, R515A, R515B, R471A, R1224, R1234yf, R1234ze, R1233, and R1336. This combination is preferred in that the GWP (t-CO₂) of the entire system can be reduced.

In the present specification, HFO-1132 refers to HFO-1132a, HFO-1132(E), or HFO-1132(Z). R1224 refers to HCFO-1224yd(E), HCFO-1224yd(Z), HCFO-1224zb(E), HCFO-1224zb(Z), HCFO-1224xe(E), or HCFO-1224xe(Z). R1234 refers to HFO-1234yf, HFO-1234ze(E), or HFO-1234ze(Z). R1233 refers to HCFO-1233zd(E), HCFO-1233zd(Z), or HCFO-1233xf. R1336 refers to HFO-1336mzz(E), HFO-1336mzz(Z), HFO-1336mcy, HFO-1336mcz(E), or HFO-1336mez(Z). When these HFOs and HCFOs are used as refrigerants, the notations “HFO-” and “HCFO-” may be omitted, and the refrigerants may be referred to as “RXX,” such as R1234yf.

The refrigeration apparatus of the present disclosure is preferably an air-conditioning system, a refrigerator, a freezer, a water cooler, an ice maker, a refrigerated showcase, a freezing showcase, a freezing and refrigerating unit, a refrigerating machine for freezing and refrigerating warehouses, an air-conditioning system for vehicles, a turbo refrigerating machine, or a screw refrigerating machine.

The refrigeration apparatus of the present disclosure is more preferably a household air-conditioning system, an air-conditioning system for business use, an industrial air-conditioning system, or a multi-split air-conditioning system for buildings.

Item 1

A refrigeration apparatus comprising:

-   a user-side heat transfer cycle configured to circulate a user-side     refrigerant; -   a heat-source-side heat transfer cycle configured to circulate a     heat-source-side refrigerant; and -   a cascade heat exchanger configured to exchange heat between the     user-side refrigerant and the heat-source-side refrigerant, -   the user-side refrigerant having a boiling point of -30° C. or more     and 25° C. or less, and the heat-source-side refrigerant having a     boiling point of -55° C. or more and less than -30° C.

Item 2

The refrigeration apparatus according to Item 1, wherein the heat-source-side heat transfer cycle is a vapor compression refrigeration cycle comprising a heat-source-side compressor, a heat-source-side heat exchanger, a heat-source-side pressure-reducing device, and a heat-source-side cascade heat exchanger.

Item 3

The refrigeration apparatus according to Item 1 or 2, wherein the user-side heat transfer cycle is a vapor compression refrigeration cycle comprising a user-side compressor, a user-side heat exchanger, a user-side pressure-reducing device, and a user-side cascade heat exchanger.

Item 4

The refrigeration apparatus according to Item 1 or 2, wherein the user-side heat transfer cycle is a heat transfer cycle comprising a pump, a user-side heat exchanger, and a user-side cascade heat exchanger.

Item 5

The refrigeration apparatus according to any one of Items 1 to 4, wherein flow directions of the heat-source-side refrigerant and the user-side refrigerant are in countercurrent flow in the cascade heat exchanger.

Item 6

The refrigeration apparatus according to any one of Items 1 to 5, wherein the heat-source-side refrigerant has a burning velocity of 10 cm/s or less, and the user-side refrigerant has a burning velocity of 3 cm/s or less.

Item 7

The refrigeration apparatus according to any one of Items 1 to 6, wherein the heat-source-side refrigerant is classified as Class 2L by ASHRAE, and the user-side refrigerant is classified as Class A1 by ASHPAE.

Item 8

The refrigeration apparatus according to any one of Items 1 to 5, wherein the heat-source-side refrigerant comprises HFO-1123 and/or HFO-1132.

Item 9

The refrigeration apparatus according to any one of Items 1 to 7, wherein the heat-source-side refrigerant is R32, R452B, or R454B, and the user-side refrigerant is at least one member selected from the group consisting of R513A, R515A, R515B, R1224, R1234yf, R1234ze, R1233, and R1336.

Item 10

The refrigeration apparatus according to any one of Items 1 to 8, wherein the heat-source-side refrigerant comprises HFO-1132, and the user-side refrigerant is at least one member selected from the group consisting of R513A, R515A, R515B, R471A, R1224, R1234yf, R1234ze, R1233, and R1336.

Item 11

The refrigeration apparatus according to any one of Items 1 to 10, which is an air-conditioning system, a refrigerator, a freezer, a water cooler, an ice maker, a refrigerated showcase, a freezing showcase, a freezing and refrigerating unit, a refrigerating machine for freezing and refrigerating warehouses, an air-conditioning system for vehicles, a turbo refrigerating machine, or a screw refrigerating machine.

Item 12

The refrigeration apparatus according to any one of Items 1 to 10, which is a household air-conditioning system, an air-conditioning system for business use, an industrial air-conditioning system, or a multi-split air-conditioning system for buildings.

EXAMPLES

The present disclosure is described below with reference to Examples; however, the present disclosure is not limited to these Examples and the like.

The GWP of the entire system was calculated using the following formula.

GWP (t-CO₂) of entire system = (GWP of heat-source-side refrigerant) × (amount of heat-source-side refrigerant put in) + (GWP of user-side refrigerant) × (amount of user-side refrigerant put in)

The lower these values, the less the impact on global warming.

A refrigeration apparatus was operated by circulating the user-side refrigerants and the heat-source-side refrigerants shown in Table 2 in the user-side heat transfer cycle and the heat-source-side heat transfer cycle, respectively, as shown in FIG. 1 . The COP ratio and capacity ratio on the heat source side (both as ratios (%) relative to those of R410A), the burning velocities (cm/s) of the heat-source-side refrigerants and the user-side refrigerants, and the saturation vapor pressure (gauge pressure) (MPaG) of the user-side refrigerants at 25° C. were determined and are shown in Tables 2 and 3.

TABLE 2 Heat-source-sidereligement User-side refrigerant Heat-source-side GWP User side System Heat-source-side CCP Heat-source-side Capacity Heat-source-side Burning velocity User-side Saturation vapor pressure (25^C) User-sideBurning velocity cm/s t-CO₂ vsR410A % vsR410A % cm/s MPaG cm/s Comp. Ex.1 R32 CO2 675 1 3 102 110 6.7 6.33 0 Comp. Ex.2 R32 Water 675 0 3 102 110 6.7 -0.1 0 Ex.1 R410A R513A 2088 631 37 100 100 0 0.61 0 Ex.2 R410A R515B 2088 292 22 100 100 0 0.39 0 Ex.3 R410A R1234ze(E) 2058 1 9 100 100 0 0.40 1.5 Ex.4 R410A R1335mcy 2088 10 10 100 100 0 0.14 0 Ex.5 R410A R1336mzz(E) 2088 10 10 100 100 0 0.09 0 Ex.6 R410A R1224yd(Z) 2058 1 9 100 100 0 0.05 0 Ex7 R32 R513A 675 631 30 102 110 6.7 0.61 0 Ex.8 R32 R515B 675 292 16 102 110 6.7 0.39 0 Ex.9 R32 R1234ze(E) 675 1 3 102 110 6.7 0.40 1.5 Ex.10 R32 R1336mcy 675 10 3 102 110 6.7 0.14 0 Ex.11 R32 R1335mzz(E) 675 10 3 102 110 6.7 0.09 0 Ex.12 R32 R1224yd(Z) 675 1 3 102 110 6.7 0.05 0 Ex.13 R454B R513A 466 631 30 102 97 5.0 0.61 0 Ex.14 R454B R515B 466 292 15 102 97 5.0 0.39 0 Ex.15 R454B R1234ze(E) 456 1 2 102 97 5.0 0.40 1.5 Ex.16 R454B R1336mcy 456 10 3 102 97 5.0 0.14 0 Ex.17 R454B R1335mzz(E) 466 10 3 102 97 50 0.09 0 Ex. 18 R454B R1224yd(Z) 456 1 2 102 97 5.0 0.05 0 Ex.19 R452B R513A 698 631 31 102 99 3.5 0.51 0 Ex.20 R452B R515B 698 292 16 102 99 3.5 0.39 0 Ex.21 R452B R1234ze(E) 698 1 3 102 99 3.5 0.40 1.5 Ex.22 R452B R1336mcy 698 10 102 99 3.5 0.14 0 Ex.23 R452B R1336mzz(E) 698 10 4 102 99 3.5 0.09 0 Ex.24 R452B R1224yd(Z) 698 1 3 102 99 3.5 0.05 0 Ex.25 R454C R513A 146 631 28 103 66 1.6 0.61 0 Ex.26 R454C R515B 146 292 13 103 66 1.6 0.39 0 Ex.27 R454C R1234ze(E) 146 1 1 103 66 1.6 0.40 1.5 Ex.28 R454C R1336mcy 146 1 1 103 66 1.6 0.14 0 Ex.29 R454C R1336mzz(E) 146 10 103 66 1.6 0.09 0 Ex.30 R454C R1224yd(Z) 146 10 1 103 66 1.6 0.05 0

TABLE 3 Heat-source-side refrigerant User-side refrigerant GWP Heat-source side Heat-source-side Heat- source side User-side User-side Heat-source-side User side System CCP Capacity Burning velocity Saturation vapor pressure (25° C.) Burning velocity i-CO₂ sR410A % ysR410A % cm/s MPaG cnvs Ex\31 R1132E/R1234yf=2367 R513A 3 631 27 103 60 2.5 0.61 0 Ex.32 R1132ER1234yf=23/67 R515B 3 292 13 103 60 2.5 0.39 0 Ex\33 R1132E/R1234yf=23/67 R1234ze(E) 3 1 0 103 60 2.5 \.40 1.5 Ex\34 R1132E/R1234yf=23/67 R1336mcy 3 1 0 103 60 2.5 0.14 0 Ex.35 R1132E/R1234yf=23/67 R1336mzz(E) 3 10 103 60 2.5 0.09 0 Ex\36 R1132E/R1234yf=23/67 R1224yd(Z) 3 10 0 103 60 2.5 0.05 0 Ex\37 R1132E/R1234yf=30/70 R513A 3 631 27 102 64 3.0 0.61 0 Ex.38 R1132E/R1234yf=30/70 R515B 3 292 13 102 64 30 0.39 0 Ex\39 R1132E/R1234yf=30/70 R1234ze(E) 3 1 0 102 64 3.0 0.40 1.5 Ex.40 R1132E/R1234yf=30/70 R1335mcy 3 1 0 102 64 3.0 0.14 0 !Ex.41 R1132E/R1234yf=30/70 R1336mzz(E) 3 10 0 102 64 3.0: 0.09 0 Ex.42 R1132E/R1234yf=30/70 R1224yd(Z) 3 10 0 102 64 3.0 0.05 0 Ex\43 R1132E/R1234yf=35/65 R513A 3 631 27 102 67 3.5 0.61 0 Ex.44 R1132E/R1234yf=35/65 R515B 3 292 13 102 67 3.5 0.39 0 Ex.45 R1132E/R1234yf=35/65 R1234ze(E) 3 1 0 102 67 3.5 \.40 1.5 Ex.46 R1132E/R1234yf=35/65 R1336mcy 3 1 0 102 67 3.5 0.14 0 Ex.47 R1132E/R1234yf=35/65 R1335mzz(E) 3 10 0 102 67 3.5 0.09 0 Ex.48 R1132E/R1234yf=35/65 R1224yd(Z) 3 10 0 102 67 3.5 0.05 0 Ex.49 R1132E/R1234yf/R32=15/41/44 R513A 299 631 29 101 92 7.2 0.61 0 Ex.50 R1132E/R1234yf/R32=15/41/44 R515B 299 292 0.14 101 92 7.2 0.39 0 Ex.51 R1132E/R1234yf/R32=15/41/44 R1234ze(E) 299 1 1 101 92 7.2 0.40 1.5 Ex.52 R1132E/R1234yf/R32=15/41/44 R1336mcy 299 1 1 101 92 7.2 0.14 0 Ex.53 R1 132E/R1234yf/R32=15/4 1/44 :R1335mzz(E) 299 10 2 101 92 7.2 0.09 0 Ex.54 R1132E/R1234yf/R32=15/41/44 R1224yd(Z) 299 10 2 101 92 7.2 0.05 0 Ex.55 R1132E/R1123/R1234yf/R32=25/25/25/22 R513A 150 631 28 98 97 7.0 0.61 0 Ex.56 R1132E/R1123/R1234yf/R32=25/25/28/22 R515B 150 292 13 98 97 7.0 0.39 0 Ex.57 R1132E/R1123/R1234yf/R32=25/25/28/22 R1234ze(E) 150 1 1 98 97 7.0 0.40 1.5 Ex.58 R1132E/R1123/R1234yf/R32=25/25/28/22 R1336mcy 150 1 1 98 97 7.0 0.14 0 Ex.59 R1132E/R1123/R1234yf/R32=25/25/28/22 R1336mzz(E) 150 10 1 98 97 7.0 009 0 Ex.60 R1132E/R1123/R1234yf/R32=25/25/28/22 R1224yd(Z) 150 10 1 98 97 7 0.05 0 Ex.61 R1123/R1234yf/R32=40/16/44 R513A 298 631 29 98 107 5.0 0.61 0 Ex.62 R1123/R1234yf/R32=40/16/44 R515B 296 292 0.14 98 107 5.0 0.39 0 Ex.63 R1123/R1234yf/R32=40/16/44 R1234ze(E) 298 1 1 98 107 5.0 0.40 1.5 Ex.64 R1123/R1234yf/R32=40/16/44 R1336mcy 298 1 1 98 107 5.0 0.14 0 Ex.65 R1123/R1234yf/R32=40/16/44 R1336mzz(E) 298 2 98 107 5.0 0.09 0 Ex.66 R1123/R1234yf/R32=40/16/44 R1224yd(Z) 298 10 2 98 107 5.0 0.05 0 Ex.67 R1123/R1234yfR32=60/18.5/21.5 R513A 146 631 28 96 104 4.0 0.61 0 Ex.68 R1123/R1234yfR32=60/18.5/21.5 R515B 146 292 13 96 104 4.0 0.39 0 Ex.69 R1123/R1234yfR32=60/18.5/21.5 R1234ze(E) 146 1 1 96 104 4.0 0.40 1.5 Ex.70 R1123/R1234yfR32=60/18.5/21.5 R1366mcy 146 1 1 96 104 4.0 0.14 0.14 0 Ex.71 R1123/R1234yfR32=60/18.5/21.5 R1336mzz(E) 146 10 1 96 104 4.0 0.09 0 Ex.72 R1123/R1234yfR32=60/18.5/21.5 R1224yd(Z) 146 10 1 96 104 4.0 0.05 0 Ex.73 R1123/R1234yf=20/80 R513A 3 631 27 102 59 2.2 0.61 0 Ex.74 R1123/R1234yf=20/80 R515B 3 292 13 102 59 2.2 0.39 0 Ex.75 R1123/R1234yf=20/80 R1234ze(E) 3 1 0 102 59 2.2 0.40 1.5 Ex.76 R1123/R1234yf=20/80 R1335mcy 3 1 0 102 59 2.2 0.14 0 Ex.77 R1123/R1234yf=20/80 R1336mzz(E) 3 10 0 102 59 2.2 0.09 0 Ex.78 R1123/R1234yf=20/80 R1224yd(Z) 3 3 10 0 102 59 2.2 0.05 0 Ex.79 R1123/R1234yf=30/70 R513A 3 631 27 101 66 2.6 0.61 0 Ex.80 R1123/R1234yf=30/70 R515B 3 292 13 101 66 2.6 0.39 0 Ex.81 R1123/R1234yf=30/70 R1234ze(E) 3 1 0 101 66 2.6 0.40 1.5 Ex.82 R1123/R1234yf=30/70 R1336mcy 3 1 0 101 66 2.6 0.14 0 Ex.83 R1123/R1234yf=30/70 R1336mzz(E) 3 10 0 101 66 2.6 0.09 0 Ex.84 R1123/R1234yf=30/70 R1224yd(Z) 3 01 0 101 66 2.6 0.05 0

The boiling points of the refrigerants used in the Comparative Examples and the Examples are as follows.

-   R410A: -51° C. -   R32: -52° C. -   R452B: -51° C. -   R452B: -51° C. -   R454C: -46° C. -   R513A: -29° C. -   R515B: -19° C. -   R1234ze(E): -19° C. -   R1336mcy: +1° C. -   R1224yd(Z): +14° C. -   R1336mzz(E): +7° C.

The results show that in the refrigeration apparatus shown in FIG. 1 , by using a refrigerant with a relatively high density and good performance that has a boiling point of -55° C. or more and less than -30° C. as the heat-source-side refrigerant, the refrigeration cycle efficiency can be maintained within a preferable range, with a COP of 100% or more and a refrigerating capacity of 60% or more, even when a refrigerant with a boiling point of -30° C. or more and 25° C. or less is used as the user-side refrigerant.

The results also show that by using a refrigerant with a boiling point of 25° C. or less as the user-side refrigerant, its saturation vapor pressure can be made equal to or higher than atmospheric pressure. Furthermore, the results show that by using a refrigerant with a boiling point of -30° C. or more as the user-side refrigerant, its pressure can be maintained at a level that does not exceed the withstanding pressure limit of the pipe.

Description of the Reference Numerals

-   1: Refrigeration apparatus -   10: User-side heat transfer cycle -   11: User-side compressor -   12: User-side cascade heat exchanger -   13: User-side expansion valve -   14: User-side heat exchanger -   15: User-side liquid receiver -   15a: Fusible plug -   21: User-side high-pressure sensor -   22: User-side low-pressure sensor -   23: User-side discharge temperature sensor -   30: Heat-source-side heat transfer cycle -   31: Heat-source-side compressor -   32: Heat-source-side heat exchanger -   33: Heat-source-side expansion valve -   34: Heat-source-side cascade heat exchanger -   35: Cooling portion -   40: Cascade heat exchanger -   50: Control device 

1-12. (canceled)
 13. A refrigeration apparatus comprising: a user-side heat transfer cycle configured to circulate a user-side refrigerant; a heat-source-side heat transfer cycle configured to circulate a heat-source-side refrigerant; and a cascade heat exchanger configured to exchange heat between the user-side refrigerant and the heat-source-side refrigerant, wherein the heat-source-side refrigerant comprises HFO-1123 and/or HFO-1132, and the user-side refrigerant is at least one member selected from the group consisting of R513A, R515A, R515B, R471A, R1224, R1234yf, R1234ze, R1233, and R1336mcy.
 14. A refrigeration apparatus comprising: a user-side heat transfer cycle configured to circulate a user-side refrigerant; a heat-source-side heat transfer cycle configured to circulate a heat-source-side refrigerant; and a cascade heat exchanger configured to exchange heat between the user-side refrigerant and the heat-source-side refrigerant, wherein the heat-source-side refrigerant is R452B or R454B, and the user-side refrigerant is at least one member selected from the group consisting of R513A, R515A, R515B, R1224, R1234yf, R1234ze, R1233, and R1336.
 15. The refrigeration apparatus according to claim 13, wherein the heat-source-side heat transfer cycle is a vapor compression refrigeration cycle comprising a heat-source-side compressor, a heat-source-side heat exchanger, a heat-source-side pressure-reducing device, and a heat-source-side cascade heat exchanger.
 16. The refrigeration apparatus according to claim 13, wherein the user-side heat transfer cycle is a vapor compression refrigeration cycle comprising a user-side compressor, a user-side heat exchanger, a user-side pressure-reducing device, and a user-side cascade heat exchanger.
 17. The refrigeration apparatus according to claim 13, wherein the user-side heat transfer cycle is a heat transfer cycle comprising a pump, a user-side heat exchanger, and a user-side cascade heat exchanger.
 18. The refrigeration apparatus according to claim 13, wherein flow directions of the heat-source-side refrigerant and the user-side refrigerant are in countercurrent flow in the cascade heat exchanger.
 19. The refrigeration apparatus according to claim 13, wherein the heat-source-side refrigerant has a burning velocity of 10 cm/s or less, and the user-side refrigerant has a burning velocity of 3 cm/s or less.
 20. The refrigeration apparatus according to claim 13, wherein the heat-source-side refrigerant is classified as Class 2L by ASHRAE, and the user-side refrigerant is classified as Class A1 by ASHRAE.
 21. The refrigeration apparatus according to claim 13, which is an air-conditioning system, a refrigerator, a freezer, a water cooler, an ice maker, a refrigerated showcase, a freezing showcase, a freezing and refrigerating unit, a refrigerating machine for freezing and refrigerating warehouses, an air-conditioning system for vehicles, a turbo refrigerating machine, or a screw refrigerating machine.
 22. The refrigeration apparatus according to claim 13, which is a household air-conditioning system, an air-conditioning system for business use, an industrial air-conditioning system, or a multi-split air-conditioning system for buildings. 